I thought it was a compliment to both of them. Arlene obviously sees Alesha as one to beat, and sees Rachel as a real contender.
Rachel is an excellent dancer from a technical point of view, but I still think she needs to sell the dances more, as she hasn't yet got me reaching for the phone, which I've come close to at least once for almost all the 16 couples at some stage as I have no favourite this year.
On a related subject, nailing both the technique and performance of a dance in 4 days is much easier said than done. Purists may nitpick the technical aspects of dances like Mark's AT, Alesha's chacha and even Austin's paso last night, but what made the judges whip out 3 tens in all 3 examples was the performance, and on a show like Strictly where the contestants aren't even bronze medal standard, why should we expect or demand technical accuracy? Do we really believe it takes 4 days to nail the technique of a dance like the AT? If that is the case, why do professional dancers spend years honing their skills?
Having said that, when someone nails the technical side of things, this should be rewarded in the same way. It can and should be an either/or thing - 1/2 judges looking at just technique, 2/3 looking at perfomance, and when both come together the celeb gets a perfect score.
It's unreasonable to expect a celeb to excel in the technical and perfomance aspects of latin and ballroom, and unsurprisingly none of them has thus far.